Function summary

The category argument allows a specific category of the locale settings to be used for fetching a message.
Valid categories are: LC_CTYPE, LC_NUMERIC, LC_TIME, LC_COLLATE, LC_MONETARY, LC_MESSAGES and LC_ALL.

Allows you to override the current domain for a single plural message lookup.
It also allows you to specify a category.
Returns correct plural form of message identified by $singular and $plural for count $count
from domain $domain.

Gets an environment variable from available sources, and provides emulation
for unsupported or inconsistent environment variables (i.e. DOCUMENT_ROOT on
IIS, or SCRIPT_NAME in CGI mode). Also exposes some additional custom
environment information.